聚乙烯-炭黑导电材料的电阻-温度特性

自1966年观察到聚乙烯(PE)-炭黑(CB)材料有明显的电阻率正温度系数(PTC)现象以来,对其电阻-温度特性已有一些报导。但对涉及电阻测量的一些基本问题前人的看法并不相同。以测量时电压的影响为例:Meyer认为在电阻随温度上升的区间电阻随电压成指数上升,而在室温及高聚物熔点时电阻与电压无关。他认为在测量电阻时无需采用同一电压。Narkis的结果是在所有情况下电阻值皆随电压上升而成指数下降。

ON THE RESISTANCE-TEMPERATURE BEHAVIOR OF POLIYETHYLENE-CARBON BLACK CONDUCTIVE COMPOSITES

In this paper the influence of the-voltage on the resistance of polyethylene-carbon black composites has been studied, and thus the resistance-temperature behavior has been examined more accurately. The relationship between resistance and temperature could be expressed by an exponential formula: R = M. exp(N(t + 80)/(110-t)), which is coincident with temperature up to 10-30℃ below the M.P. of polyethylene depending on the carbon black content.The relationship between the expansion coefficient and temperature was compared with the PTC phenomenon of the materials. High expansion coefficient of the matrix is essential for the conductive composites to possess PTC effect.